class Building:
    def __init__(self, name):
        self.name = name

class Course:
    def __init__(self, title, building: Building):
        self.title = title
        self.building = building


class College:
    def __init__(self, name):
        self.name = name
        self.buildings = []
        self._courses = []

    def add_building(self, building: Building):
        self.buildings.append(building)

    def create_course(self, title, building: Building):
        new_course = Course(title, building)
        self._courses.append(new_course)
        return new_course

    def destroy_college(self):
        self._courses = []
        self.buildings = None